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Post by stardiamond on Aug 29, 2018 15:12:12 GMT -5
I know that it is an acceptable practice for some materials like turquoise. I noticed the seller on ebay who was selling old stock Morgan Hill mentioned that he stabilized it with sodium silicate. Years ago, I bought MH slabs and cabbed it. I generally worked around the fractures and expected cabs to still fracture. I have some pieces that were fractured and filled them with superglue. I plan to sand off the glue and soak the slabs in sodium silicate. I have plenty for gluing rough.
Is treating MH with sodium silicate acceptable? Is it something that needs to be disclosed if I wanted to sell a cab? Does treatment significantly impact selling price? Koroit was also mentioned here as something that can require stabilization.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Aug 29, 2018 16:42:29 GMT -5
Acceptable, yes. Does it need to be disclosed, yes absolutely. Even in material such as turquoise, "stabilization" (which can mean different things according to different people) and any other treatment must be disclosed. Unlike other gemstones, treatment of a piece of Morgan Hill may not affect the value a huge amount, but treatments are also disclosed for other reasons (they affect things like durability, what products may be used in cleaning, etc.). You may also want to experiment with sodium silicate before committing to doing a good piece. By itself, it is more porous and soluble in water than the silica in, say, agate (which is why sodium silica used for things like waterproofing decking needs to be regularly reapplied). Because of this, it doesn't stand up to things like repeated cleanings. Usually, folks who use it as a stabilizer or filler add epoxy resin to increase its durability. You could use an alkali as a catalyst to do the same thing, but getting the mix correct and into the rock before it sets up can be tricky. |
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Post by stardiamond on Aug 29, 2018 17:13:54 GMT -5
Thanks for the input. I started using sodium silicate to slab and what I like about it is that it comes off with water. I was surprised that the ebay seller used it to stabilize. I am going to take off the glue with a 220 soft and see what the slabs look like. Putting on the glue seems like a silly thing to do. The largest slab has a spider web of fractures on the bad side. I might try that one to test if only to see if it holds together when sawing and grinding.
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Fossilman
Cave Dweller 
Member since January 2009
Posts: 20,718 
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Post by Fossilman on Aug 30, 2018 9:57:42 GMT -5
I sell stabilized slabs, on some material.. As long as I tell the customer about it, its all good....The prices don't change on it and they still sell....
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Post by vegasjames on Aug 30, 2018 17:25:41 GMT -5
Thanks for the input. I started using sodium silicate to slab and what I like about it is that it comes off with water. I was surprised that the ebay seller used it to stabilize. I am going to take off the glue with a 220 soft and see what the slabs look like. Putting on the glue seems like a silly thing to do. The largest slab has a spider web of fractures on the bad side. I might try that one to test if only to see if it holds together when sawing and grinding. When stabilizing with sodium silicate the sodium silicate must be polymerized or chemically reacted to form a silicate. Otherwise it will simply wash away when cabbing. Many compounds will polymerize it. But you need to experiment. I have been trying to find something to polymerize it clear, no luck yet. And the second thing is to find something that polymerizes slowly. Otherwise the reaction occurs so rapidly at the surface that the polymerizer creates a "shell" that prevents the polymerizer from reaching deeper inside to polymerize the remaining sodium silicate. |
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Post by stardiamond on Aug 30, 2018 19:23:59 GMT -5
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